auxiliary verb
Definition: This word is used to express necessity or obligation, indicating that something is required or very important to do.
Example: You must finish your homework before going out to play.
intransitive verb
Definition: This word is used to express necessity or obligation, indicating that something is required or essential.
Example: You must finish your homework before you can go out.
noun
Definition: Something that is absolutely necessary or required.
Example: Comfortable shoes are a must for long walks.